Regeneration of waste sintered Nd-Fe-B magnets to fabricate anisotropic bonded magnets

Li, Xiantao; Yue, Ming; Zakotnik, M.; Liu, Weiqiang; Zhang, Dongtao; Zuo, Tao

doi:10.1016/s1002-0721(14)60478-6

Cited by 24 publications

(23 citation statements)

References 14 publications

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“…2,3 Diverse methodologies have been proposed, including the use of mechano-chemical treatment without external heating, 4 the recovery of neodymium from NdFeB magnets at high temperatures using molten magnesium metal as extractant 5 and hydrogen gas to separate the NdFeB magnets from waste. [6][7][8][9] As an alternative to these processes, rare earths and other valuable metals present in magnet scrap can be recovered and puried through leaching and solvent extraction. 2,[10][11][12] The separation and purication of metals by solvent extraction is a well-known strategy that has been used at laboratory and industrial scale for decades.…”

Section: Introductionmentioning

confidence: 99%

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

et al. 2017

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“…Another approach to reprocessing waste sintered magnets is to convert them to powders for bonded magnets application. Li et al 132 have reported on mechanical crushing and hydrogen decrepitation as approaches for reprocessing waste sintered magnets into bonded magnets. They found that the powders recycled via the hydrogen decrepitation performed better than the powder recycled via mechanical milling, although the remanence and coercivity degraded for both methods-with coercivity degrading the most.…”

Section: Reprocessing/remanufacturing/refurbishing Of Permanent Magnetsmentioning

confidence: 99%

Manufacturing Processes for Permanent Magnets: Part II—Bonding and Emerging Methods

Cui

Ormerod²,

Parker

et al. 2022

JOM

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Permanent magnets produce magnetic fields and maintain the field even in the presence of an opposing magnetic field. They are widely used in electric machines, electronics, and medical devices. Part I reviews the conventional manufacturing processes for commercial magnets, including Nd-Fe-B, Sm-Co, alnico, and ferrite in cast and sintered forms. In Part II, bonding, emerging advanced manufacturing processes, as well as magnet recycling methods are briefly reviewed for their current status, challenges, and future directions.

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“…Périgo et al [77] employed the HDDR process to recycle N42 sintered magnets to make isotropic powders and investigated the effect of recombination temperature and H 2 pressure on the magnetic properties of recycled magnets. Li et al [46,78,79] studied the influence of particle distribution and hydrogenation conditions, and found that (1) the oxygen content decreases rapidly as particle size distribution increases and (2) higher H 2 pressure during hydrogenation results in decreasing oxygen content. Both Sheridan et al [80] and Gutfleisch et al [81] used a higher processing pressure during disproportionation and avoided subsequent oxygen exposure by performing both the v-HD and s-DR processes in the same furnace.…”

Section: Recycling Via Hydrogenationmentioning

confidence: 99%

Review of High-Temperature Recovery of Rare Earth (Nd/Dy) from Magnet Waste

Firdaus

Rhamdhani

Durandet

et al. 2016

J. Sustain. Metall.

103

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Rare-earth metals, particularly neodymium, dysprosium, and praseodymium are becoming increasingly important in the transition to a green economy due to their essential role in permanent magnet applications such as in electric motors and generators. With the increasingly limited rare-earth supply and complexity of processing Nd, Dy, and Pr from primary ores, recycling of rare-earth based magnets has become a necessary option to manage supply and demand. Depending on the form of the starting material (sludge or scrap), there are different routes that can be used to recover neodymium from secondary sources, ranging from hydrometallurgical (based on its primary production process), electrochemical to pyrometallurgical. Pyrometallurgical routes provide solution in cases where water is scarce and generation of waste is to be limited. This paper presents a systematic review of previous studies on the high-temperature (pyrometallurgical) recovery of rare earths from magnets. The features and conditions at which the recycling processes had been studied are mapped and evaluated technically. The review also highlights the reaction mechanisms, behaviors of the rare-earth elements, and the formation of intermediate compounds in high-temperature recycling processes. Recommendations for further scientific research to enable the development of recovery of the rare-earth and magnet recycling are also presented.

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Regeneration of waste sintered Nd-Fe-B magnets to fabricate anisotropic bonded magnets

Cited by 24 publications

References 14 publications

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

Manufacturing Processes for Permanent Magnets: Part II—Bonding and Emerging Methods

Review of High-Temperature Recovery of Rare Earth (Nd/Dy) from Magnet Waste

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